This invention relates in general to respiratory ventilators, and in particular to a respiratory ventilator having automatic flow calibration of respiratory gas delivered in accord with immediately preceding breath data.
Certain respiratory diseases not only require patient special care with respect to physical activity and attendant exertion levels, but also require specialized mechanical augmentation to permit the patient to simply accomplish the act of breathing. Thus, while lung disfunction, lung tissue degradation, autonomic nervous system disability, etc. can significantly interfere with proper inhalation and exhalation action and thereby deprive an individual of adequate oxygenation and attendant carbon dioxide removal, employment of a ventilator for positive respiratory regulation can result in a highly beneficial contribution toward life quality. As required, and in accord with actual maladies encountered, such ventilator therapy can be administered in association with physical activity-monitoring to thereby provide a treatment program to the patient that achieves improved comfort in day-to-day functions along with medically acceptable respiratory levels.
Ventilators presently in service generally operate under constant parameters that are pre-set such that inhalation and expiration of air or oxygen-enriched air does not automatically vary, but, instead, can be changed manually if a health care provider in charge of a treatment program determines such modification is desired. Therefore, volume, pressure, and delivery duration of inspiratory air or oxygen-enriched air are quantitatively estimated in accord with standard expectations usually present under a majority of circumstances in similarly-situated patients. While these parameters may adequately serve most patients most of the time, any patients whose needs do not fit expectations must endure at least partially ineffective ventilation until manual readjustment of the ventilator can be completed. Further, of course, any momentary change of respiratory needs such as that encountered in momentary exertion for whatever reason is not addressed by a ventilator whose delivery capabilities can be modified only through manual adjustment unless a technician just happens to be present.
In view of these limitations, it is apparent that a need is present for a ventilator apparatus that is more responsive to patient needs. It is therefore a primary object of the present invention to provide a ventilator that is capable of sensing untoward respiratory activity and thereafter responding to such activity.
Another object of the present invention is to provide a ventilator whose respiratory sensor member comparatively monitors incremental exhalation flow parameters during a single exhalation and automatically calibrates ventilator output to maintain or change such output in accord with such exhalation parameters.
Yet another object of the present invention is to provide a ventilator whose calibrateable parameters include volume, pressure, and delivery-duration of air or oxygen-enriched air as administered to a patient.
These and other objects of the present invention will become apparent throughout the description thereof which now follows.